Flexible electronic system with wire bonds

ABSTRACT

Generally discussed herein are systems and apparatuses that can include apparatuses, systems, or method for a flexible, wire bonded device. According to an example an apparatus can include (1) a first rigid circuit comprising a first plurality of bond pads proximate to a first edge of the first rigid circuit, (2) a second rigid circuit comprising a second plurality of bond pads proximate to a first edge of the second rigid circuit, the second rigid circuit adjacent the first rigid circuit and the first edge of the second rigid circuit facing the first edge of the first rigid circuit, or (3) a first plurality of wire bonded wires, each wire bonded wire of the first plurality of wire bonded wires electrically and mechanically connected to a bond pad of the first plurality of bond pads and a bond pad of the second plurality of bond pads.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.14/227,805, filed Mar. 27, 2014, which is incorporated by referenceherein in its entirety.

TECHNICAL FIELD

Examples generally relate to flexible circuit architectures and methods.More specifically, examples relate to using wire bonds to create aflexible circuit architecture.

TECHNICAL BACKGROUND

Wearable electronic systems can be flexible to help the electronicsystem conform to body curvature(s). In many cases the bending must berepeatable. For example, in a bracelet system, the bracelet can conformto the curvature of the human body part that the bracelet goes aroundwhen worn or can be nearly or entirely flat when not being worn. Theshape of the part can vary from person to person, thus making theflexibility of the bracelet important so that a single bracelet can fita variety of body parts.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, which are not necessarily drawn to scale, like numeralsmay describe similar components in different views. Like numerals havingdifferent letter suffixes may represent different instances of similarcomponents. The drawings illustrate generally, by way of example, butnot by way of limitation, various embodiments discussed in the presentdocument.

FIG. 1 shows a block diagram of a prior art flexible circuit.

FIG. 2A shows a block diagram of a side view of an example of a flexiblecircuit according to one or more embodiments.

FIG. 2B shows a block diagram of a top view of an example of a flexiblecircuit according to one or more embodiments.

FIG. 3A shows a block diagram of an example of a flexible circuitaccording to one or more embodiments.

FIG. 3B shows a block diagram of an example of another flexible circuitaccording to one or more embodiments.

FIG. 4 shows a block diagram of an example of a two dimensional systemaccording to one or more embodiments.

FIG. 5 shows a flow diagram of a technique for making a flexible circuitaccording to one or more embodiments.

FIG. 6 shows a block diagram of a prior art wire bond.

FIG. 7 shows a block diagram of an example of a wire bond according toone or more

FIG. 8 shows a block diagram of an example of a system for wire bondinga wire to a bond pad.

DESCRIPTION OF EMBODIMENTS

Examples in this disclosure relate generally to flexible circuitarchitectures and methods. More specifically, examples relate to usingwire bonds to create a flexible circuit architecture.

Discussed herein is a reduced cost method to obtain a flexible (e.g.,bendable) electric (e.g., electronic) system, such as can be used forwearable electric systems or the “internet-of-things”. A problem withcurrent flexible electric systems includes a lack of deformable,conductive interconnects between rigid parts of the flexible electricsystem. Another problem with current flexible electric systems is aprohibitive cost to manufacture the system. To be more widelymarketable, flexible electric systems should be manufactured at areduced cost with respect to current manufacturing costs.

A desirable characteristic of flexible (e.g., wearable) electric systemsis the ability to use a diverse array of electric components in theflexible electric system. Radios and sensors can be part of a flexiblesystem, so as to allow a currently rigid system, such as a smart phone,to be implemented in a flexible electric form. Many current electriccomponents come pre-packaged, or are only available in a certain form ofpackaging.

An approach to making a wearable electric system out of currentlyavailable components can benefit from a technique or architecture thatallows a wide variety of shapes and sizes of electric components to beused therewith. For example, a communications sub-system or radio caninclude a plurality of small individual chips such as a power amplifier,a low noise amplifier, or a digital to analog converter, among others.Each of these components can be, for example, wire bonded to a substrateand packaged for surface mounting, such as in a Surface Mount (SMT)package. As many of these sorts of systems, apparatuses, or componentsare pre-packaged and can be cost efficient, a wearable system thatallows prepackaged components to be used therein can be beneficial.

FIG. 1 shows a block diagram of an example of a prior art flexiblesystem 100. The system 100 includes a combination of a rigid board 102and a flex board 104 technology. As used herein “rigid” means either notbendable or an area that has a bending radius that is significantlylarger than a bending radius required to conform to a curved surface ofinterest.

The flex board 104 is integrated (i.e. merged) with the rigid board 102using vias or Plated Through Holes (PTH). A problem with this technologyincludes a cost that is higher than the cost goals for flexible systems.Another problem with such a flexible system, can include “winding” thetraces in a sort of spring pattern on the flexible board 102 so that thetraces do not break when the flexible board 102 is bent. The routing andplating of such traces is more complicated and consumes more real spacethan in a non-flexible system or in a flexible system that does notinclude traces on a flexible board.

In contrast to the prior art flexible circuit systems, wire bonded wirescan provide a flexible interconnect between rigid circuit segments, suchas to provide a system (e.g., a wearable system) that can be composed ofrigid circuit (e.g., non-bendable) segments. The rigid circuit segmentscan be homogeneous, heterogeneous, or a combination thereof. A systemwith wire bonds between rigid circuit segments can provide bothflexibility and interconnect density, two parameters that are usually inconflict with each other in bendable and to a certain degree,stretchable systems.

The conflict can be explained as follows. In a bendable system, theinterconnects are generally comprised of metals, such as copper (Cu),that have an elongation in an elastic region that is small or negligible(e.g., Cu<0.1%). Straight Cu interconnects can undergo plastic yieldingwith very low deformations, which can result in interconnect cracking. Acommon solution to this problem is to use meandering traces (i.e.two-dimensional spring-like or meandering traces). However, thesemeandering traces can take up a significant amount of space, thuslimiting the frequency of the interconnect lines and reducing the tracedensity. The distance between the meandering traces can depend on thetrace width, and can reach values above one millimeter. Anothershortcoming of meandering interconnect lines can include deformation andstress concentrations occurring where the meandering lines connect tothe rigid circuit segments, creating weak points that can reduce thereliability of the entire system.

Another solution includes the so called rigid-flex, such as shown inFIG. 1, which currently is relatively costly and from a manufacturingperspective, is certainly more costly than using wire bonding to connectrigid circuit segments.

Wire bonding technology is considered to be cost effective, especiallyif Cu or aluminum (Al) wires are used. Wire bonding can provide asegment (e.g., rigid circuit) to segment interconnect at a reduced costor at a higher density than meandering traces. In addition, anypackaging technology (e.g., rigid segments) can be interconnectedtogether to form a bendable or flexible system, as long as the packagingtechnology includes pads to which wires can be wire bonded.

One feature of a wire bonded circuit system is that heterogeneouscomponents can be connected using wire bonds. There are at least twoadvantages that this capability can provide. One is that differentcomponents, such as a processor (e.g., Central Processing Unit (CPU)), amemory, a radio, a Micro ElectroMechanical System (MEMS), wireless,graphics, chipset, or an analog component are typically assembled usingdifferent technologies. (e.g., wire bonding, surface mount, or BGA,among others). By adjusting a package design (if necessary) so that atleast the facing sides of directly adjacent rigid circuits include wirebond pads, a flexible system can be built without necessitating auniform packaging technology. Another advantage is that existing,off-the-shelf components, or rigid circuit segments can be used, such asto reduce cost and time to market. The wire bonded wires can besufficiently long to enable bendability. During the wire bonding processthe wires can be guided such as to allow for additional length orlimited spring-characteristics for multiple bending cycles. Multiplebending cycles is in contrast to systems with wires that need to be bentonly once. A single bending cycle can be realized in a bracelet systemwhere the electronics are bent as they are mounted in a bent case andnever bent again.

FIG. 2A shows a block diagram of a side view of an example of a system200 that can include wire bonded wires 202, according to one or moreembodiments. FIG. 2B shows a block diagram of a top view of an exampleof the system 200 of FIG. 2A.

The system 200 can include a plurality of rigid circuits (e.g., acomponent 204, a Wafer Level Package (WLP) 206, or a pin out board 208)electrically connected using one or more wires 202 (e.g., through wirebonds). The rigid circuit can include a variety of components of varyingshapes and sizes. For example, the rigid circuits can include one ormore of components 204, such as can include a flip chip package, asurface mount package, a Ball Grid Array (BGA) package, a PTH part orpackage (e.g., a Dual In-Line Package (DIP) or a Pin Grid Array (PGA)part or package), a leadless chip part or package, a Thin Small-OutlinePackage (TSOP) part or package, a Land Grid Array (LGA) part or package,a Printed Circuit Board (PCB) or a combination thereof, among others.The rigid circuit can include a wafer level package 206, such as caninclude one or more dies or components embedded or integrated in a mold218. The components in the mold 218 can be electrically coupled duringmanufacturing of the wafer level package 206. The wafer level package206 includes an integrated pin out layer 220 that includes a pluralityof interconnects (e.g., a wire bond pad, SMT bond pad, flip chip bondpad, BGA bond pad, a male or female connection feature, or the like),such as to provide electrical access to the one or more dies orcomponents embedded in the mold 218. The component 204 can beelectrically coupled (e.g., soldered or connected through a mating maleor female connection feature) to an interconnect provided in the pin outlayer 220.

The wires 202 can be insulated, such as by surrounding the wire with adielectric material or other insulator, such as a plastic, a polymer, ora dielectric (e.g., silicon dioxide or silicon nitride), among others.The wire can be spray coated with an insulating or dielectric material,such as before or after wire bonding the wire. This material can bedried or cured after the spray coating.

The wires 202 can be encapsulated in an insulating material 214. Theinsulating material 214 can include an elastomer material, such as aPolyDiMethylSiloxane (PDMS) or a synthetic rubber, among others. Usinginsulated wires or encapsulated wires can help prevent a short circuitor help increase the longevity or ruggedness of the wires 202. A wirewith an increased ruggedness can include a wire that can be bent moretimes or bent in a manner that would not otherwise be allowed withoutthe wire breaking.

The wires 202 can be include Au, Cu, Al, or alloys thereof, amongothers. Other materials may be used if a wire bond process for them isavailable, and if the mechanical properties allow bending. If thebending is limited to a single time (for instance to fit the system intoa rigid casing, such as i.e. a ring), pure Al may also be used as a lowcost alternative.

The pin out board 208 (e.g., PCB) can include a plurality of bond pads210 situated thereon. The bond pads 210 can be electrically coupled to atrace, via, or component 204, such as to provide electrical access tothe component, trace, or via. The bond pads 210 can be configured forattaching a wire thereto, such as through wire bonding. The bond pads210 can be proximate an edge 212 of the pin out board 208. The bond pads208 proximate an edge of a first pin out board can include the samenumber of bond pads as a number of bond pads proximate an edge of asecond pin out board that is directly adjacent to the side of the firstpin out board, such as shown in FIG. 2B. The edge of the first pin outboard that includes the bond pads proximate thereto can face the edge ofthe second pin out board that includes the bond pads proximate thereto.The bond pads 210 can be situated anywhere on the pin out board 208.That is, the bond pads 210 do not need to be situated proximate the edgeof the pin out board 208, but can be situated more central to the pinout board 208 than proximate the edge.

The bond pads 210 can include a pitch that allows for a needed length ofthe wire-bond wire (e.g., depends on bending radius of the wire or therigid circuit segment). The bond pad pitch can be between aboutforty-five micrometers and about sixty-five micrometers. The bond pads210 can be a standard size. A bond pad size used can be a function of aminimum pitch. The bond pad size or shape does not need to be the samefor all pads. The wire bond pads 210 can include one or more rows ofbond pads, such as can be dependent on a needed or desired interconnectdensity. The surface of the bond pads 210 can be any conductor (e.g.,metal) that can used as a surface finish for wire bonding and iscompatible with the wire 202. Materials for surface finishes include,but are not limited to: gold (Au), Cu, Al, palladium (Pd), stacksthereof, or combinations thereof.

The rigid circuits can be situated on, or at least partially in anflexible carrier 216. The flexible carrier 216 or the insulatingmaterial 214 can help stabilize the system 200, such as by providing thesystem 200 with more rigidity than would be provided without theflexible carrier 216 or the insulating material 214. The flexiblecarrier 216 can help limit the flexibility of the system 200, such as tohelp protect the wires 202 from breaking. The flexible carrier 216 caninclude a flexible adhesive tape material. In general, the flexiblecarrier 216 can include any flexible material that the rigid circuitscan be mounted on, such as by glue, epoxy, solder, or other adhesive.The flexible carrier 216 may not be needed for mechanical rigidity. Theflexible carrier 216 can help define a distance between the components(e.g., rigid circuit segments, and can help prevent breaking of the wirebond wires or stress on the wire bond connection. The flexible carrier216 can include elastomer, resin, a polymer (e.g., PolyethyleneTerephthalate (PET), PolyDiMethylSiloxane (PDMS), or Polyimide (PI)), ora combination thereof.

Using the system 200, different package technologies can beinterconnected with wire bonds, enabling bendability in the wire bondregions. The system 200 can be prone to wire-bond breaking, as thesystem can be held together by just the wire bonds. The components(e.g., rigid circuit segments) can be mounted on the flexible carrier216 (e.g., an adhesive tape or where the flexible carrier includes noelectrical functionality). The flexible carrier 216 can have cut outs orrecesses therein to fit components therein or therethrough. The flexiblecarrier 216 can provide mechanical support for the wire bond wires.

The rigid circuits can be rotated or displaced translationally (e.g., toincrease a distance between two rigid circuits) with respect to oneanother. The rigid circuits can rotate, with respect to another rigidcircuit, about an axis that is generally parallel or perpendicular toone of their edges. Note that rotation or translation of one rigidcircuit with respect to another is generally arbitrary and not limitedto rotation about an axis that is perpendicular or parallel to an edgeof the rigid circuit. For example, if an edge of one rigid circuit isset at a thirty degree angle with respect to an edge of another rigidcircuit, the rotational axis may not be generally parallel orperpendicular to an edge of either rigid circuit. One or more edges of arigid circuit may or may not be substantially parallel to an edge of anadjacent second rigid circuit.

Wire bonding is a well-established technique to provide electricalinterconnects between components. Two or more rigid circuit segmentsinterconnected by wire bonded wires can be rotated relative to eachother and can provide a flexible, stretchable, or bendable system. Thebending radius or angle of a bend can be limited by the length of ashortest wire in a given set of wire bonds or the distance between thetwo rigid circuit segments that the wire of the wire bond connects. Asystem that includes wire bonded wires between rigid circuit segmentscan help enable the “Internet of Things” (i.e. the internetworking ofobjects) by creating a flexible (e.g., wearable) system that includes areduced development time (e.g., as compared to the system of FIG. 1),such as by allowing a way to interconnect existing rigid circuitsegments or components packaged with various packaging techniques. Asmall design change may be needed to add traces connected to bond padsthat can be wire-bonded to, so as to provide electrical access to one ormore components of the component or the rigid circuit segment.

FIGS. 3A and 3B illustrate block diagrams of examples of how a wirebonded flexible or bendable system 300A and 300B, respectively, can lookwhen bent. The system 300A-B can be bent (e.g., flexed) to fit into abracelet, ring, earring, glasses, clothing, or pendant, among others.The housing, or part of the housing, into which the system 300A-B canfit is outlined with the dashed lines 302A and 302B, respectively. Thesystem 300A-B can also be bent in the opposite direction and in manyother configurations. The system 300A of FIG. 3A is more heterogeneous(e.g., includes rigid circuit segments that have a greater variety oflengths, widths, or heights) than the system 300B of FIG. 3B. FIG. 3Billustrates a bent system 300B in which the rigid circuit segments aremanufactured using a similar or same packaging technology, such as tomake the overall lengths, widths, or heights of the rigid circuitsegments substantially the same. By including rigid circuit segmentsthat include overall lengths, widths, or heights that are morehomogeneous, an overall maximum form factor (indicated by the dottedarrow 304A and 304B, respectively) an be reduced. A reduced form factorcan provide more space for other components, such as a battery or canreduce the overall thickness of the system 300A-B, such as to create asystem 300A-B with a smaller overall profile.

While the FIGS. 2A, 2B, 3A, and 3B generally illustrate one dimensionalbendable systems (e.g., generally linear systems), it will be understoodthat two or even three dimensional systems can be built using techniquesof this disclosure. To build a two dimensional system, the bond pads onone rigid circuit segment can be on two sides (e.g., perpendicularsides) that share a common vertex. An example of such a two dimensionalsystem is shown in FIG. 4. To build a three dimensional system, a twodimensional system can include a one dimensional or another twodimensional system stacked thereon, such by using a material to supportthe stacked system or provide space between the two systems.

FIG. 4 shows a block diagram of an example of a two dimensional system400 according to one or more embodiments. The system 400 can include aplurality of rigid circuit segments. Each rigid circuit segment caninclude a plurality of bond pads proximate an edge of the rigid circuitsegment. A plurality of wires to be wire bonded can be encased in aninsulated ribbon 402. The insulated ribbon 402 can be generally flat.The wires 202 in the insulated ribbon can be situated side-by-side, suchas with a distance between adjacent wires being approximately the sameas a distance between centers of adjacent bond pads which the wires areto be wire bonded to.

FIG. 5 shows a flow diagram of a technique 500 for manufacturing abendable or flexible system according to one or more embodiments. At502, rigid circuit segments can be situated on a flexible carrier. At504, rigid circuit segments can be electrically or mechanicallyconnected with a wire bond. The wires to be wire bonded can bepre-insulated, such as by using a wire with an insulating coating. Thetechnique 500 can include spray coating an insulating material onto thewire bonded wires. Spray coating can be completed over substantially theentire surface of the system, such as to protect the system with aninsulator (e.g., dielectric) material. The spray coating can be limitedto the wire bonds, such as to only insulate the wires or the wire bonds.The insulating material can be deposited onto the rigid circuit segmentsand the flexible carrier. The insulating material may not adhere tononmetallic areas. In such a case, the insulating material can beremoved, such as by blowing or spraying the insulating material away.The insulating material can include a polymer or a similar material.Additives to the polymer can provide control of the viscosity of theinsulating material, wetting to the metal wires, or thickness of thecoated insulating material, such as after drying or curing. The spraycoating process and material can be tailored in its properties so thatafter drying or curing the final insulating material has a desiredthickness, such as between about one hundred nanometers and tenmicrometers. Even when using a wire with an insulated coating, the wirebond (e.g., the electrical or mechanical connection between the wire andthe rigid circuit segment) can still be exposed (e.g., not insulated).This exposed portion of the wire bond can be insulated by spray coatingor other technique of coupling an insulating material to the wire bond.

The technique 500 can include molding a region between wire bonded wiresor rigid circuit segments with a molding material, such as an elastomermaterial. The thickness of the molding material can be such that thewire bonded wires are covered (e.g., entirely covered). The technique500 can include curing the molding material.

The following description regards techniques for making a wire bond.

In stretchable (e.g., bendable or wearable) electronics interconnectsbetween a rigid material (e.g., a silicon die) and stretchable traces ona stretchable substrate need to be made compliant to accommodate astrain at an interconnection region, such as to prevent interconnectionfailure, such as during stretching (e.g., cyclic stretching) of theelectronics. In a state of the art wire bond process, wire bondinterconnects tend to fail at the neck of the wire bond. Another problemfaced in the state of the art wire bond process can include making arobust wire bond joint on a component (e.g., die) placed on a soft orcompliant material, such as PolyDiMethylSiloxane (PDMS). An ultrasonicor thermosonic wire bond requires the substrate to be rigid during thewire bonding process. This is an industry wide problem and no knowneffective solutions have been published.

FIG. 6 shows a block diagram of a prior art system 600 that includes awire bond. The system 600 can include a wire bonded die 602 encapsulatedin a stretchable material 604A or 604B, such as PDMS.

FIG. 7, shows a block diagram of an example of a wire bonded system 700,according to one or more embodiments. FIG. 8 shows an example of asystem for creating a wire bond according to one or more embodiments.

One or more bond pads 210 can be situated on a substrate 710 (e.g., acompliant substrate such as PDMS). A soft or conductive material 702A,702B, 702C, or 702D, such as solder or adhesive conductive material(e.g., Anisotropic Conductive Film (ACF)) can be applied to a die pad(e.g., on the top of a die 708 below the soft compliant material 702A-B)and a wire bond pad 210. A wedge bonder 802 can be used to firmly placea wire 202 on the compliant material 702A-D. The wire 202 and compliantmaterial 702A-D can be heated, such as locally heated by a fiber laser804, to make a metallurgical spot solder joint. The material in the areawhere there is a connection between the compliant material 702A-D, thewire 202, and the pad 210 can be considered a bond joint. The conductivematerial 702A-D can include a low temperature solder such as tin bismuth(SnBi).

The wedge bonder 802 can be used to make a wire 202 meander between thedie 708 and wire bond pad 210 to accommodate stretching of the substrate710, such as during use conditions. The wire 202 can include one or morewires in a round or flat ribbon 402. The flat ribbon 402 can helpincrease a contact area between the wire 202 and the pad 210.

The force used to keep the wire 202 in place can be adjusted to allowthe wire 202 to make a firm contact with the compliant material 702A-D,the die 708, die pad, or the pad 210, such as without causing the diepad or trace pad to deform or depress in the substrate 710. Ametallurgical bond can be made by laser spot soldering while the wire isheld down by the wedge bonder 802 (e.g., a capillary).

Laser soldering can be accomplished using an UltraViolet (UV), Infrared(IR), or a green laser, among others. A fiber laser can be attached tothe wire bond capillary of the wedge bonder 802 or placed near the wirebond capillary. The laser 804 can be moved in tandem with the wedgebonder 802.

EXAMPLES AND NOTES

The present subject matter may be described by way of several examples.

Example 1 can include or use subject matter (such as an apparatus, amethod, a means for performing acts, or a device readable memoryincluding instructions that, when performed by the device, can cause thedevice to perform acts), such as can include or use (1) a first rigidcircuit comprising a first plurality of bond pads proximate to a firstedge of the first rigid circuit, (2) a second rigid circuit comprising asecond plurality of bond pads proximate to a first edge of the secondrigid circuit, the second rigid circuit adjacent the first rigid circuitand the first edge of the second rigid circuit facing the first edge ofthe first rigid circuit, or (3) a first plurality of wire bonded wires,each wire bonded wire of the first plurality of wire bonded wireselectrically and mechanically connected to a bond pad of the firstplurality of bond pads and a bond pad of the second plurality of bondpads such that the first rigid circuit is free to rotate with respect tothe second rigid circuit about a rotational axis generally parallel tothe first edge of the first rigid circuit.

Example 2 can include or use, or can optionally be combined with thesubject matter of Example 1, to include or use a flexible carrier,wherein the first rigid circuit and the second rigid circuit aresituated on the flexible carrier.

Example 3 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 1-2, to include or useinsulating material covering substantially all of the first plurality ofwire bonded wires.

Example 4 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 1-3, to include or useinsulating material covering wire bond joints on the first plurality ofbond pads.

Example 5 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 1-4, to include or use amolding material surrounding the first plurality of wire bonded wires ina region between the first rigid circuit and the second rigid circuit.

Example 6 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 1-5, to include or use,wherein the first rigid circuit further comprises a third plurality ofbond pads situated proximate a second edge of the first rigid circuit,wherein the first edge of the first rigid circuit is opposite the secondedge of the first rigid circuit. Example 6 can include or use (1) athird rigid circuit comprising a fourth plurality of bond pads situatedproximate a first edge of the third rigid circuit, the first edge of thethird rigid circuit facing the second edge of the first rigid circuit,or (2) a second plurality of wire bonded wires, each wire bonded wire ofthe second plurality of wire bonded wires electrically and mechanicallyconnected to a bond pad of the third plurality of bond pads and a bondpad of the fourth plurality of bond pads such that the third rigidcircuit is free to rotate with respect to the first rigid circuit abouta rotational axis generally parallel to the second edge of the firstrigid circuit.

Example 7 can include or use, or can optionally be combined with thesubject matter of Example 6, to include or use a flexible carrier,wherein the first rigid circuit, second rigid circuit, and third rigidcircuit are situated on the flexible carrier.

Example 8 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 1-7, to include or use,wherein the first plurality of wires are mostly encapsulated,side-by-side, in a generally flat insulated ribbon.

Example 9 can include or use subject matter (such as an apparatus, amethod, a means for performing acts, or a device readable memoryincluding instructions that, when performed by the device, can cause thedevice to perform acts), such as can include or use (1) situating afirst rigid circuit on an flexible carrier, the first rigid circuitincluding a first plurality of bond pads situated proximate a first edgeof the first rigid circuit, (2) situating a second rigid circuit on theflexible carrier, the second rigid circuit comprising a second pluralityof bond pads proximate to a first edge of the second rigid circuit, thefirst edge of the second rigid circuit facing the first edge of thefirst rigid circuit, or (3) wire bonding each wire of a first pluralityof wires to a respective bond pad of the first plurality of bond padsand a respective bond pad of the second plurality of bond pads such thatthe first rigid circuit is free to rotate about a rotational axisgenerally parallel to the first edge of the first rigid circuit.

Example 10 can include or use, or can optionally be combined with thesubject matter of Example 9, to include or use spraying an insulatingmaterial on the first plurality of wires.

Example 11 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 9-10, to include or usespraying insulating material on a wire bond joint on the first pluralityof bond pads.

Example 12 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 9-11, to include or usesituating a molding material around the wire bonded wires in a regionbetween the first rigid circuit and the second rigid circuit.

Example 13 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 9-12, to include or use,wherein wire bonding each wire of the plurality of wires includes (1)situating a wire of the plurality of wires in a capillary of a wedgebonder, (2) situating the wire on a compliant adhesive material, or (3)melting the compliant adhesive material.

Example 14 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 9-13, to include or use,wherein the compliant adhesive material includes a solder or anAnisotropic Conductive Film (ACF) and melting the compliant adhesivematerial includes heating the compliant adhesive material using a laser.

Example 15 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 9-14, to include or use,wherein (1) the first rigid circuit further comprises a third pluralityof bond pads situated proximate a second edge of the first rigid circuitor (2) the first edge and the second edge of the first rigid circuitshare a common vertex. Example 15 can include or use (1) situating athird rigid circuit on the flexible carrier, the third rigid circuitcomprising a fourth plurality of bond pads situated proximate a firstedge of the third rigid circuit, the first edge of the third rigidcircuit facing the second edge of the first rigid circuit, or (2) wirebonding each wire of a second plurality of wires to a respective bondpad of the third plurality of bond pads and a respective bond pad of thefourth plurality of bond pads.

Example 16 can include or use subject matter (such as an apparatus, amethod, a means for performing acts, or a device readable memoryincluding instructions that, when performed by the device, can cause thedevice to perform acts), such as can include or use (1) a first rigidcircuit comprising a first plurality of bond pads proximate to a firstedge of the first rigid circuit and a second plurality of bond padsproximate a second edge of the first rigid circuit, wherein the firstedge and the second edge of the first rigid circuit share a commonvertex, (2) a second rigid circuit comprising a third plurality of bondpads proximate to a first edge of the second rigid circuit, the secondrigid circuit adjacent the first rigid circuit and the first edge of thesecond rigid circuit facing the first edge of the first rigid circuit,(3) a third rigid circuit comprising a fourth plurality of bond padsproximate a first edge of the third rigid circuit, the first edge of thethird rigid circuit facing the second edge of the first rigid circuit,(4) a first plurality of wire bonded wires, each wire bonded wire of thefirst plurality of wire bonded wires electrically and mechanicallyconnected to a bond pad of the first plurality of bond pads and a bondpad of the third plurality of bond pads such that the first rigidcircuit is free to rotate with respect to the second rigid circuit abouta rotational axis generally parallel to the first edge of the firstrigid circuit, or (5) a second plurality of wire bonded wires, each wirebonded wire of the second plurality of wire bonded wires electricallyand mechanically connected to a bond pad of the second plurality of bondpads and a bond pad of the fourth plurality of bond pads.

Example 17 can include or use, or can optionally be combined with thesubject matter of Example 16, to include or use an flexible carrier,wherein the first rigid circuit, second rigid circuit, and third rigidcircuit are situated on the flexible carrier.

Example 18 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 16-17, to include or useinsulating material covering substantially all of the first plurality ofwire bonded wires.

Example 19 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 16-18, to include or useinsulating material covering wire bond joints on the first plurality ofbond pads.

Example 19 can include or use, or can optionally be combined with thesubject matter of at least one of Examples 16-18, to include or use amolding material surrounding the first plurality of wire bonded wires ina region between the first rigid circuit and the second rigid circuit.

The above detailed description includes references to the accompanyingdrawings, which form a part of the detailed description. The drawingsshow, by way of illustration, specific embodiments in which methods,apparatuses, and systems discussed herein can be practiced. Theseembodiments are also referred to herein as “examples.” Such examples caninclude elements in addition to those shown or described. However, thepresent inventors also contemplate examples in which only those elementsshown or described are provided. Moreover, the present inventors alsocontemplate examples using any combination or permutation of thoseelements shown or described (or one or more aspects thereof), eitherwith respect to a particular example (or one or more aspects thereof),or with respect to other examples (or one or more aspects thereof) shownor described herein.

In this document, the terms “a” or “an” are used, as is common in patentdocuments, to include one or more than one, independent of any otherinstances or usages of “at least one” or “one or more.” In thisdocument, the term “or” is used to refer to a nonexclusive or, such that“A or B” includes “A but not B,” “B but not A,” and “A and B,” unlessotherwise indicated. In this document, the terms “including” and “inwhich” are used as the plain-English equivalents of the respective terms“comprising” and “wherein.” Also, in the following claims, the terms“including” and “comprising” are open-ended, that is, a system, device,article, composition, formulation, or process that includes elements inaddition to those listed after such a term in a claim are still deemedto fall within the scope of that claim. Moreover, in the followingclaims, the terms “first,” “second,” and “third,” etc. are used merelyas labels, and are not intended to impose numerical requirements ontheir objects.

As used herein, a “-” (dash) used when referring to a reference numbermeans “or”, in the non-exclusive sense discussed in the previousparagraph, of all elements within the range indicated by the dash. Forexample, 103A-B means a nonexclusive “or” of the elements in the range{103A, 103B}, such that 103A-103B includes “103A but not 103B”, “103Bbut not 103A”, and “103A and 103B”.

The above description is intended to be illustrative, and notrestrictive. For example, the above-described examples (or one or moreaspects thereof) may be used in combination with each other. Otherembodiments can be used, such as by one of ordinary skill in the artupon reviewing the above description. The Abstract is provided to complywith 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain thenature of the technical disclosure. It is submitted with theunderstanding that it will not be used to interpret or limit the scopeor meaning of the claims. Also, in the above Detailed Description,various features may be grouped together to streamline the disclosure.This should not be interpreted as intending that an unclaimed disclosedfeature is essential to any claim. Rather, inventive subject matter maylie in less than all features of a particular disclosed embodiment.Thus, the following claims are hereby incorporated into the DetailedDescription as examples or embodiments, with each claim standing on itsown as a separate embodiment, and it is contemplated that suchembodiments can be combined with each other in various combinations orpermutations. The scope of the invention should be determined withreference to the appended claims, along with the full scope ofequivalents to which such claims are entitled.

What is claimed is:
 1. A method comprising: situating a first rigidcircuit including an electrical component encapsulated in a mold andwith a pinout layer directly on the mold on an adhesive tape of aflexible, stretchable carrier, the first rigid circuit including a firstplurality of bond pads situated proximate to a first edge of the firstrigid circuit, the pinout layer on a surface of the mold facing awayfrom the flexible, stretchable carrier; directly electrically connectinga second electrical component to the pinout layer; situating a secondrigid circuit on the flexible, stretchable carrier, the second rigidcircuit comprising a second plurality of bond pads proximate to a firstedge of the second rigid circuit, the first edge of the second rigidcircuit facing the first edge of the first rigid circuit; and wirebonding each wire of a first plurality of wires to a respective bond padof the first plurality of bond pads and a respective bond pad of thesecond plurality of bond pads such that the first rigid circuit is freeto rotate about a rotational axis generally parallel to the first edgeof the first rigid circuit and move translationally away from the secondrigid circuit.
 2. The method of claim 1, wherein the flexible,stretchable carrier includes elastomer or polydimethylsiloxane (PDMS).3. The method of claim 1, further comprising spraying an insulatingmaterial on the first plurality of wires and the first and second rigidcircuits.
 4. The method of claim 3, further comprising removing thesprayed insulating material from non-metallic regions of the first andsecond rigid circuits and the first plurality of wires.
 5. The method ofclaim 1, further comprising forming first and second recesses in theflexible, stretchable carrier and situating the first rigid circuit inthe first recess and situating the second rigid circuit in the secondrecess.
 6. The method of claim 1, further comprising situating anelastomer material in a region between the first and second rigidcircuits such that the elastomer material covers the wire bonded firstplurality of wires.
 7. The method of claim 1, wherein the first rigidcircuit includes a pin out board and a component, the pin out boardbetween the component and the flexible, stretchable carrier.
 8. Themethod of claim 7, wherein the second rigid circuit includes a waferlevel package and a pin out board, the wafer level package between thepin out board and the flexible, stretchable carrier.
 9. The method ofclaim 1, further comprising spraying insulating material on a wire bondjoint on the first plurality of bond pads.
 10. The method of claim 1,wherein wire bonding each wire of the plurality of wires includes:situating a wire of the plurality of wires in a capillary of a wedgebonder; situating the wire on a compliant adhesive material; and meltingthe compliant adhesive material.
 11. The method of claim 10, wherein thecompliant adhesive material includes a solder or an AnisotropicConductive Film (ACF) and melting the compliant adhesive materialincludes heating the compliant adhesive material using a laser.
 12. Themethod of claim 1, wherein the first rigid circuit further comprises athird. plurality of bond pads situated proximate a second edge of thefirst rigid circuit, wherein the first edge and the second edge of thefirst rigid circuit share a common vertex, and the method furthercomprises: situating a third rigid circuit on the flexible carrier, thethird rigid circuit comprising a fourth plurality of bond pads situatedproximate a first edge of the third rigid circuit, the first edge of thethird rigid circuit facing the second edge of the first rigid circuit;and wire bonding each wire of a second plurality of wires to arespective bond pad of the third plurality of bond pads and a respectivebond pad of the fourth plurality of bond pads.
 13. A method comprising:situating a first rigid circuit including an electrical componentencapsulated in a mold on an adhesive tape of a flexible, stretchablecarrier, the first rigid circuit including a first plurality of bondpads situated proximate a first edge of the first rigid circuit, thefirst rigid circuitry further including a pinout layer on a surface ofthe mold facing away from the flexible, stretchable carrier; directlyelectrically connecting a second electrical component to the pinoutlayer; situating a second rigid circuit on the flexible, stretchablecarrier, the second rigid circuit comprising a second plurality of bondpads proximate to a first edge of the second rigid circuit; and wirebonding each wire of a first plurality of wires to a respective bond padof the first plurality of bond pads and a respective bond pad of thesecond plurality of bond pads such that the first rigid circuit is freeto rotate and move transiationally away from the second rigid circuit.14. The method of claim 13, wherein the flexible, stretchable carrierincludes elastomer or polydimethylsiloxane (PDMS) or an adhesive tape.15. The method of claim 13, wherein the first edge of the first rigidcircuit is not parallel to the first edge of the second rigid circuit.16. The method of claim 13, further comprising forming first and secondrecesses in the flexible, stretchable carrier and situating the firstrigid circuit in the first recess and situating the second rigid circuitin the second recess.
 17. The method of claim 13, wherein the firstrigid circuit includes a pin out board and a component, the pin outboard between the component and the flexible, stretchable carrier. 18.The method of claim 17, wherein the second rigid circuit includes awafer level package and a pin out board, the wafer level package betweenthe pin out board and the flexible, stretchable carrier.